Pantone to CMYK accuracy in Quark XPress

Someone in a forum I visit asked why he gets incorrect color when converting from Pantone to CMYK in Quark XPress. While I do not have the answer (though I have a guess or two), I do have a solution. It's not the most elegant solution, but it works.

Step 1:Create a Pantone color in Quark Xpress. For this tip, I chose Pantone 542. (See diagram at right)

Step 2:Using the Model drop down menu, change the color model to LAB and write down the 3 values (percentage numbers) you are presented with. Do not hit the OK button.

Step 3:Using the Model drop down menu again, change the color model to CMYK. You should notice a pretty drastic color shift, though it varies by color. Hit the OK button. (See diagram at right)

Step 4:Re-open the Pantone color you just converted again. It should look like the diagram at right.

Step 5:Change the color Model back to LAB with the Model drop down menu. You should notice that the LAB numbers have changed. Take the LAB numbers your wrote down earlier in Step 2 and re-enter them exactly the same. The "new" color sample should now look like the original Pantone Color, and the "Original" sample is what the direct CMYK conversion would have been. (See diagram at right)

Step 6:All that's left is to change the color Model drop down menu back to CMYK and un-check the Spot Color radio button. (See diagram at right)

That's it. Your newly converted Pantone to CMYK color should be much more accurate. As an example, I created 3 colors for the diagram below. The first was the original Pantone 542 color with no adjustments at all. The second is the same Pantone Color, but I simply changed the color MODEl to CMYK directly. The third is my "fixed" color conversion. Though it isn't 100% perfect, it's probably 98% perfect, and the other 2% wouldn't show up on a press anyway due to ink gain.

I'm pretty sure the conversion from Pantone to CMYK is based on the Pantone-approved numbers, so you get whole percentage-point numbers and minimal color plates. The LAB to CMYK conversion you demonstrate gives impossible to print numbers.

I tried this with Pantone 123 and the LAB to CMYK gives me a C3 M17.2 Y91 K0.1. I don't know that a printing press can print a 0.1% black plate. The Pantone-approved conversion is C0 M24 Y94 K0. Maybe not as close a match but easy to print on press.

Creativebits is a blog about Creativity, Graphic Design, Adobe, Apple and other related subjects.